| 程涌,胡煜昭,李丕优,卢萍.滇东会泽地区下寒武统筇竹寺组黑色岩系微量元素地球化学特征及其古环境演化[J].地质找矿论丛,2019,34(3):416-422 |
| 滇东会泽地区下寒武统筇竹寺组黑色岩系微量元素地球化学特征及其古环境演化 |
| The geochemical characteristics of trace elements and paleoenvironmental evolution of black rock series in the lower Cambrian Qiongzhusi Formation from Huize area, eastern Yunnan province |
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| DOI：10.6053/j.issn.1001-1412.2019.03.011 |
| 中文关键词: 筇竹寺组 黑色岩系 微量元素 地球化学 沉积环境 会泽地区 云南省 |
| 英文关键词:Qiongzhusi Formation black rock series trace elements geochemistry sedimentary environment Huize area Yunnan province |
| 基金项目:云南省应用基础研究计划项目（编号：2015FD052，编号：2017FD129）资助。 |
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| 中文摘要: |
| 黑色岩系在全球分布广泛，层位稳定，对于探讨地球浅部的化学元素的分布规律与机制，重塑地球演化的历史和过程、开发利用矿产资源及保护环境等方面具有重要意义。通过对滇东会泽县大海乡老林村下寒武统筇竹寺组黑色岩系剖面的系统采样和微量元素地球化学分析结果表明：①微量元素Pb、Zn强烈富集，B、Cu、V、U相对富集，Sr强烈亏损；w（Th）/w（U）值明显低于大陆地壳平均值，说明该样品总体受到的风化程度低，可以用来反映古环境及其演化信息。②w（B）/w（Ga）值反映古水体盐度变化为咸水→半咸水→淡水→半咸水，经历了一个先降低再升高的过程。③亲氧元素Sr强烈亏损，指示筇竹寺组沉积时期还原环境占主导地位；w（V）/w（V+Ni）值表明该沉积时期古水介质总体为水体分层不强的厌氧环境，下部沉积泥质灰岩和粉砂质白云岩时经历了短暂的氧化环境，中上部沉积碳质页岩时经历了短暂的硫化环境。④w（Sr）/w（Cu）值指示该沉积时期古气候总体为温暖潮湿，下部沉积时期经历了短暂的炎热干旱气候，这与下部具高盐度咸水和氧化的古水介质相对应。此研究对于该区黑色岩系矿床形成背景的探讨、矿产资源勘查及页岩气选区评价具有一定的指导意义。 |
| 英文摘要: |
| Black rock series are widely distributed at certain horizons in the world. They are significant in respects of discussion of pattern and mechanism of distribution of chemical elements in the shallow earth, reconstruction of history and process of the earth evolution, exploitation and utilization of mineral resources and environmental protection. The trace element analysis of systematic samples collected from section of black rock series of Lower Cambrian Qionzhusi Formation at Laolin village of Dahai town of Huize county in the east Yunnan province show that:① Pb and Zn are highly enriched, B, Cu, V and U relatively enriched, Sr strongly depleted, w(Th)/w(U) of the samples significantly lower than that of the continental crust average value and all this is the indication of low overall weathering degree thus can be used as the information of paleo-environment; ② the value of w(V)/w(V+Ni) reflects the salinity change of decrease and increase of ancient water body from saline water-semi-saline water to fresh water-semi-saline water; ③ strong depletion of oxyphile element Sr indicates the dominant reductive environment of Qiongzhusi formation; w(V)/w(V+Ni) illustrates an anaerobic environment of the ancient water body without strong stratification and in this sedimentary period is generally, and the water experience a transient oxidation environment when the argillaceous limestone and silty dolomite forms in the lower part, and the water is in a transient sulfide environment when the carbonaceous shale forms in the middle and upper part. ④ w(Sr)/w(Cu) indicates that the paleoclimate in this sedimentary period was generally warm and humid, while there is a short hot and dry climate when lower part sediment, which corresponds to the ancient water medium with high salinity and oxidation in the lower part. This study is of certain guiding significance for learning the formation background of black rock series ore deposits, exporting mineral resources and evaluating and selecting target area of shale gas. |
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